One in eight condominiums in Vancouver were unoccupied in 2014, according to a report given to city officials Tuesday, seeming to bolster the suspicion that many of those properties are being purchased as investments.

However, the report didn't find a relationship between rising home prices and the overall rate of non-occupancy in the city. A total of 4.8% of all homes in Vancouver, including single-family homes, row houses, condos, and rental apartments, weren’t occupied in 2014, a rate researchers said was roughly in line...